Add support for LISP tunneling

Add support for LISP tunneling

LISP is an experimental layer 3 tunneling protocol, described in RFC
6830.  This patch adds support for LISP tunneling.  Since LISP
encapsulated packets do not carry an Ethernet header, it is removed
before encapsulation, and added with hardcoded source and destination
MAC addresses after decapsulation.  The harcoded MAC chosen for this
purpose is the locally administered address 02:00:00:00:00:00.  Flow
actions can be used to rewrite this MAC for correct reception.  As such,
this patch is intended to be used for static network configurations, or
with a LISP capable controller.

Signed-off-by: Lorand Jakab <lojakab@cisco.com>
Signed-off-by: Kyle Mestery <kmestery@cisco.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>